Impact modification of thermoplastics with ethylene/α-olefin interpolymers

Abstract

Impact modified compositions having good impact performance can be made from a thermoplastic (e.g., a polyolefin such as polypropylene or HDPE) and a multi-block ethylene / α-olefin interpolymer. The compositions are easily molded and often have particular utility in making, for example, automotive facia, parts and other household articles.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a Continuation-In-Part Application to U.S. application Ser. No. 11 / 376,838, filed Mar. 15, 2006 now U.S. Pat. No. 7,863,379, which claims priority to PCT Application No. PCT / US2005 / 008917, filed on Mar. 17, 2005, which in turn claims priority to U.S. Provisional Application No. 60 / 553,906, filed Mar. 17, 2004 and also claims priority to U.S. Provisional Application Ser. No. 60 / 717,928 filed Sep. 16, 2005, and the present application also claims the benefit of U.S. Provisional Application No. 61 / 163,937, filed on Mar. 27, 2009. The presented application is also related to the following U.S. Provisional Applications having Ser. Nos. 61 / 024,674; 61 / 024,688; 61 / 024,693; 61 / 024,696; 61 / 024,701; and 61 / 024,705, all filed on Jan. 30, 2008. For purposes of United States patent practice, the contents of the aforementioned applications are herein incorporated by reference to the extent that the language is not inconsistent with ...

AI Technical Summary

Benefits of technology

[0004]Thermoplastic olefins (TPOs) are often produced from blends of an elastomeric material such as ethylene / propylene rubber (EPM) or ethylene / propylene diene monomer terpolymer (EPDM) and a more rigid material such as isotactic polypropylene. Other materials or components can be added into the formulation depending upon the application, including oil, fillers, and cross-linking agents. TPOs are often characterized by a balance of stiffness (modulus) and low temperature impact, good chemical resistance and broad use temperatures. Because of features such as these, TPOs are used in many applications, including automotive facia and wire and cable operations, rigid packaging, molded articles, instrument panels, and the like.

[0008]Thus, while the development of new lower modulus polymers such as Flexomer™ Polyolefins by Union Carbide or Exact™ polymers by Exxon has aided the TPO marketplace, there continues to be a need for other more advanced, cost-effective polymers for compounding with thermoplastics (e.g., polyolefins such as polypropylene or HDPE) to improve or maintain modulus and / or impact performance at room temperature or below.

Problems solved by technology

It is well known that narrow molecular weight distribution linear polymers disadvantageously have low shear sensitivity or low I10 / I2 value, which limits the extrudability of such polymers.

Additionally, such polymers possessed low melt elasticity, causing problems in melt fabrication such as film forming processes or blow molding processes (e.g., sustaining a bubble in the blown film process, or sag in the blow molding process etc.).

Finally, such resins also experienced surface melt fracture properties at relatively low extrusion rates thereby processing unacceptably and causing surface irregularities in the finished product.

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